DE112004001370B4 - Elastomeric nucleus replacement - Google Patents

Abstract

Disc nucleus replacement, comprising:
an elastomeric sheath (12) disposed about a rod (14), a portion of the sheath (12) being adapted to slide along the rod (14); and
a shell press (18) adapted to cause a portion of the shell (12) to slide along the rod (14) from a first position to a second position, the shell (12) being in a first position in a first position is in an uncompressed configuration and the sheath (12) is in a second position in a compressed configuration, with pleats of the sheath (12) relaxing radially outward from the rod (14).

Description

Field of application of the invention

The The present invention relates to a prosthetic disc nucleus and in particular a prosthetic disc nucleus which is an elastomeric nucleus Shell and comprises a medial rod. The sliding sleeve can be narrowed in a Form are implanted and then by an axial contraction the shell widened again, whereupon the rod in the prosthetic Disc nucleus causes this one enlarged part of the volume of the intervertebral space.

Background of the invention

The Intervertebral disc is made up of three distinct ones Tissues together: the annulus fibrosis, nucleus pulposus and the vertebral endplate. The treatment of disc dysfunctions becomes common made by an exchange of the disc core (prosthetic Nuclear implantation). This process is important because of this the other disc tissues maintaining the annulus and end plates, where they can keep their functions. The priority tasks The prosthetic core implantation is the recovery of the disc space and relieving the compressive stress on this pulley component by a distribution of a substantial part of the stress.

The patent US 5800549 A Bao describes implanting one or more (four implants are used in one embodiment) of dehydrated prosthetic hydrogel cores into the intervertebral disc space. After implantation of these implanted nuclei, they hydrogenate to a shape that adapts to the natural nucleus. Bao also describes an insertion device for inserting an elastic prosthetic spinal cord core into the disc space. The insertion device comprises a force transmission element for rapid deployment of the prosthesis in the disc space to prevent permanent deformation of the elastic prosthetic nucleus. These implants are relatively large according to the teachings of Bao and must be compressed to fit the subsequent hydration through the device. The embodiments of Bao have several disadvantages. On the one hand, the size of the implant increases according to the maximum volume due to the hydration. It is not possible to exactly match the implant size according to the required intervertebral disc space (previous core), so that the optimal pressure on the vertebrae can not be applied. Furthermore, during the hydration process, the core-receiving shell occupies a smaller space than the intervertebral space and is thus free to move during hydration to move to a less suitable location. In addition, a high pressure must be applied to the implant to be passed through the insertion device. This process may result in the implant being inserted into the intervertebral disc space at a high rate and may possibly damage the annulus.

The patent US 6022376 A von Assell describes a capsular prosthetic disc nucleus for implantation in a human intervertebral disc space which consists essentially of an inelastic and thus limited sheath surrounding an amorphous core. The casing of Assell is installed through the skin into a damaged disc space through a flap formed in the annulus. The sheath may be implanted in an empty state and then filled with a core, which is accomplished by the use of a syringe or catheter designed to fit through the constricted sheath, or alternatively may be the core containing sheath are implanted.

In both of these cases after Assell becomes a final Capsule volume achieved after hydration of the hydrogel core. Thus the doctrine of Assell also has the same as that of Bao den inherent disadvantage of a small implant volume at the time implantation, with volume increasing over time. In addition, the length of the After Assell flap about 12 mm and has a height of about 6 mm for use a denture body on, which has a small axial diameter of 7 mm. The relatively large Dimensions of the flap are one of them dependent and insurmountable Disadvantage of the device of Assell. Furthermore, the core picks up Shell during the Time of hydration a smaller space than in its final position and is free to move to a less advantageous position to move.

The patent US 6306177 B1 von Felt describes the use of a curable polyurethane biomaterial composition which is capable of being mixed at the time of use to form a flowable composition and initiate healing. Although the Felt system apparently solves the problem of not filling the available space completely, Felt's system also has several disadvantages. These disadvantages include, among others. Disadvantage the undisclosed biostability of the thermosetting polyurethane, the complicated erforderli Tissue hardening and hardening time, which may be too short (less than a few minutes), with last-minute changes impossible.

The patent US 6676665 B2 by Foley et al. describes an instrument for treating the spine which comprises an elongated member having a deformable rear end portion, and is partially formed of a flexible and preferably elastic material. The aft end portion has an initial configuration for abutting disposition to a vertebral body and a deformed configuration including at least one outwardly projecting projection for removing at least a portion of the vertebral body.

The elongated Element preferably comprises a rod element, a casing element and an actuating mechanism to continue a relative linear displacement between the rod and the Wrapper element one to the outside directed deformation of the rear end portion of the sheath element to effect. In one embodiment will the instrument used to create a cavity at the firm cancellous bone within the vertebral body to build. In another embodiment, the instrument used to reduce a compression break. In another another embodiment The instrument is used to create a disc-shaped space between the adjacent vertebral bodies.

The WO 00/44319 A1 describes an expandable spacer to separate two vertebrae of a spine. The spacer comprises a tube having a plurality of slots. The slots define at least two axially offset boom. Upon axial compression of the tube, the cantilevers individually protrude from the surface to form the extended spacer shape.

Even though Many prosthetic disc devices have been described in the literature there is still a need for improvement in terms of ease of manufacture and operation.

These The object is solved by the subject matter of patent claim 1. further developments are in the dependent claims specified.

Summary of the invention

The The present invention relates to an elastomeric nucleus replacement, as described in more detail below.

It Will be in connection with an embodiment of the present Invention, an intervertebral nucleus replacement is provided, which is an elastomeric Cover includes, which is mounted around a rod, wherein a part of the shell in such a way is arranged to slide along the rod and wherein this continue a casing press includes, which carried out so is to be a part of the shell along the rod from a first position to a second position to slide, with the shell in the first position in a non-compressed arrangement is present and in a second position, the shell in a compressed Position is present, with folds in the sheath directed radially from the rod to the outside form.

Of the Disc nucleus replacement may have one or more of the following features include. For example, a stop at the rear end of the rod be arranged and the casing press can be a back part of the case press against the stop. A removable mounting ring may be a part of the shell on the Hold staff. The rod may comprise a removable part. Of the Rod can be flexible, and can be brought into an arcuate shape. The rod may be made of a shape memory alloy or be made for example a polymer. The ends of the Staff can be fastened together. The rod can be withdrawn from the shell and removed. The folds of the envelope may be either uniform or altogether unequal outward unfold in a directed manner. The distance between the folds of the envelope can vary axially along the rod. On one side of the case you can do more Wrinkles occur as on the other side of the sheath. It can be an anchorage for connecting the spinal cord structure present be. Furthermore, a guide wire for introduction the shell to be available.

Brief description of the drawings

The Drawings include in:

1 a side cross-sectional view of an embodiment of the present invention in a non-compressed form, comprising a sheath which is disposed over the rod;

2 a cross-sectional side view of the embodiment 1 in a compressed form (ie, the sheath is compressed in an extended orientation and along the length of the rod) prior to removal of an open medial rod;

3 a cross-sectional side view of the embodiment 1 in the compressed form after removal of the open medial rod;

4 shows a perspective sectional view of an embodiment of an elastomeric prosthetic disc nucleus implant according to the present invention;

5 FIG. 4 is a side cross-sectional view of a disc space showing in situ two compressed elastomeric prosthetic disc nucleus implants according to the present invention; FIG.

6 a cross-sectional side view of another embodiment of the present invention, wherein this has a medial rod with a memory shape in the compressed form after removal of the open medial rod;

7 a cross-sectional side view of another embodiment of the present invention, which shows a medial rod with a memory shape in the compressed form after removal of the open medial rod;

8th a view of an intervertebral disc space showing a compressed elastomeric prosthetic disc nucleus implant having in situ a medial rod with a shape of memory according to the present invention;

9 a plan view of the implant of 8th in an arranged form in a disc space, with an adjacent vertebrae removed for clarity;

10 a plan view of the implant of 8th shown in an arranged form in a disc space with a correspondingly arranged adjacent vertebrae for clarity;

11 a view of an embodiment of the invention in which an anchor is mounted in an end plate;

12 a plan view of an embodiment of the invention, in which a sleeve is slipped over a guide wire; and

13 another plan view of an embodiment of the invention with a sheath, which is slipped over a guide wire, in which the sheath extends along the guide wire.

Description of the embodiments

The following will be on 1 Reference is made in which an elastomeric prosthetic disc implant 10 is shown in the form prior to implantation according to an embodiment of the present invention. An elastomeric shell 12 , which is shown in oblong shape, can around the inner rod 14 be mounted. Some non-limiting examples of elastomers used for the sheath design 12 are suitable polyurethane, latex, natural rubber, silicone rubber, nylon and a shape memory polymer. The rod 14 may be cylindrical in shape with a generally circular cross-section, the invention not being limited to this shape, and the rod 14 may also have a different shape or cross-section. An attack 16 can be at or near one end of the bar 14 be arranged, which is either attached thereto or integral with the shell 12 and / or the staff 14 is formed. The inner rod 14 and the stop 16 may be formed from a rigid material such as hardened plastic or a metal, and may be of unitary construction (eg, integral), or may be constructed of a plurality of parts formed by one or more joints 13 are connected.

A casing press 18 Can be used to cover the case 12 from a first uncompressed and narrow mold into a compressed and thicker mold, the casing 12 until the stop 16 is compressed. The implant 10 In its uncompressed form, it is designed to fit into a small hole (for example 6 mm or less in diameter) and can be stretched under the skin to a diameter which is larger than the entry hole.

In front during compression, the maximum thickness of the shell is much thinner than after compression; which allows a minimally invasive process and allows the process to be performed with a standard instrument which is for a percutaneous spine surgery suitable is.

A fastening ring 20 Can be used to cover the case 12 before and / or after being pressed by the press 18 to keep.

The following will be on 2 Referring to Figure 1, which shows an elastomeric prosthetic spinal nucleus implant after compression in the compressed position to place it in place within the intervertebral disc space (not shown). The casing press 18 was along the inner bar 14 until the stop 16 moved further (for example, in the sense of the representation to the left). Fold the envelope 12 buckle outward into the compressed arrangement in an accordion-like manner. The size of the folds of the envelope 12 which after Outside curved, is a function of the end position of the casing press 18 , This position of the envelope press 18 may be predetermined prior to the procedure using, for example, radiological or other means. The casing press 18 can first from the mounting ring 20 be solved to this along the bar 14 to move. Subsequently, the fastening ring 20 at an end position on the inner rod 14 taken by one of the many means comprising a pawl and a hook, by a snapper, a thread, etc ..

A section 22 of the inner rod 14 which does not encase or through the shell 12 is open, can now from the implant 10 be separated (separated and removed), such as by breaking the remainder of the inner rod 14 or by unscrewing the section 22 at one of the plurality of predetermined locations, such as the connection 13 , as in 3 shown.

4 Figure 3 is a perspective, broken-away view of an elastomeric prosthetic disc nucleus implant 10 in a final compressed form.

5 Figure 4 is a cross-sectional view of an intervertebral disc space with two compressed elastomeric prosthetic disc nucleus implants 10 shown in situ.

According to some embodiments of the invention, the rod 14 be flexible. In such an embodiment, the rod 14 without limitation, it may be formed of a flexible plastic (e.g., polyurethane, nylon, shape memory polymer) or flexible metal (e.g., stainless steel, shape memory alloy such as NITINOL), and may be constructed similarly to a catheter having guidewires such as those in angioplasty be used. This allows the implant 10 , a curved shape such as a bow ( 6 ) or a ring ( 7 ) to accept. These embodiments are expected to find use in a variety of medical applications, including, but not limited to, a spinal cord replacement or a miniscus replacement or replacement elsewhere where it is necessary to exchange or add tissue, with the added benefit of the cushioning effect elastomeric shell 12 ,

In an embodiment in which the rod 14 is made of a shape memory alloy or a polymer, the rod 14 be held in a straight arrangement by an external force and assume the desired curved arrangement when the external force is removed. The required external force, for example, by a removable rigid core within the rod 14 or be applied by a rigid tube, which the rod 14 and the shell 12 receives. In such a flexible embodiment, the two ends of the rod 14 (with any suitable connection means such as these, but not limited to screws, clips, snaps, a bonding method, ultrasonic welding, VELCRO and the like) to hold the mold.

According to a further embodiment of the invention, the inner rod 14 to guide the shell 12 guided into the intervertebral space and after the expansion of the sheath 12 withdrawn and removed from the intervertebral disc space.

The folds of the shell 12 extend in the illustrated embodiment, a total of uniformly directed to the outside. However, the invention also includes a non-uniform expansion caused by a change in the distance between the folds and the sheath 12 axially along the rod 14 can be achieved (ie axially different spaces between the folds) or alternatively by changing the number of folds in the envelope 12 on different sides of the bar 14 (ie, radially different spaces between the folds).

Combinations of axial and radial differences associated with flexible rods 14 allow almost all forms of the implant 10 , either symmetrical or asymmetrical.

8th is a cross-sectional view of an intervertebral disc space 30 , which shows a compressed elastomer prosthetic disc nucleus implant, which is a sheath 12 on a medial staff 14 having a shape memory function in situ.

According to some embodiments of the invention, the implant 10 be attached or anchored in one of the adjacent vertebral bones. This helps to leave the implant in place and prevents displacement or movement. Such an embodiment is in 9 shown, which is a plan view of the implant 10 at a location in the disc space, with the adjacent vertebra removed for purposes of illustration. An anchor 32 can be integral with the implant 10 be executed or alternatively on the implant 10 at one end either before or after the implant is attached to the adjacent vertebra. The attachment may be through one or more fasteners 34 out be formed, which may consist of non-limiting manner of screws, rivets, bolts or the like.

10 is a plan view of an implant, which is shown in its arrangement in the disc space and with a fastener 34 attached or anchored in one of the adjacent vertebrae.

11 shows another embodiment of the invention, in which an anchor 36 can be anchored in the vertebral bone by the end plate of at least one adjacent vertebra either before or after the placement of the implant.

Below is on the 12 and 13 Reference is made to an embodiment of the invention with a shell 12 show which over a guidewire 40 is arranged. The guide wire 40 can first be placed in the intervertebral disc space, as in 12 is shown. The guidewire 40 may be made of a metal rod made of a shape memory alloy and be arcuate or annular when it is inserted in the intervertebral disc space. An applicator 42 can be used to either the guidewire 40 , the case 12 or both in the intervertebral disc space before compressing the sheath 12 introduce. After the guidewire 40 is positioned, the implant can 10 into the intervertebral disc space above the guide wire 40 can be introduced in an uncompressed form, and then this can be pressed to a thicker shape, as described above. An attack 44 can be at the end of the guidewire 40 be arranged, which the shell 12 prevents it from extending the length of the guidewire 40 to move out. 13 shows the embodiment, which in 12 is shown, this being the shell 12 about half way along the guidewire 40 in the direction of the attack 44 shows. After the shell 12 the stop 44 has reached, the guidewire can 40 be tethered, leaving the sheath on the guidewire 40 in the direction of the attack 44 compressed as described above. The inner rod 14 may be hollow to the guide wire 40 take.

Claims (16)

Intervertebral nucleus replacement, comprising: one around a rod ( 14 ) arranged elastomeric shell ( 12 ), whereby a part of the envelope ( 12 ) is designed to move along the rod ( 14 ) to glide; and a jacket press ( 18 ), which is designed to prevent slippage of a part of the envelope ( 12 ) along the rod ( 14 ) from a first position to a second position, the envelope ( 12 ) is in a first position in a non-compressed arrangement and the envelope ( 12 ) is in a second position in a compressed arrangement, wherein folds of the envelope ( 12 ) radially from the rod ( 14 ) relax to the outside. The nucleus replacement according to claim 1, wherein a stop ( 16 ) at a rear part of the rod ( 14 ) and the casing press ( 18 ) is formed so that the rear end of the shell ( 12 ) against the attack ( 16 ) is pressable. The nucleus replacement according to claim 1, wherein a removable attachment ring ( 20 ) a part of the envelope ( 12 ) on the rod ( 14 ) attached. The nucleus replacement according to claim 1, wherein the rod ( 14 ) a removable part ( 22 ). The nucleus replacement according to claim 1, wherein the rod ( 14 ) is flexible. The nucleus replacement according to claim 5, wherein the rod ( 14 ) is bendable in an arcuate shape. The nucleus replacement according to claim 1, wherein the rod ( 14 ) is formed of at least one shape memory alloy and a shape memory polymer. The nucleus replacement according to claim 5, wherein the ends of the rod ( 14 ) are mountable with each other. The nucleus replacement according to claim 1, wherein the rod ( 14 ) retractable and from the shell ( 12 ) is removable. The nucleus replacement according to claim 1, wherein the folds of the envelope ( 12 ) relax uniformly outward. The nucleus replacement according to claim 1, wherein the folds of the envelope ( 12 ) unevenly outward relax. The nucleus replacement according to claim 1, wherein the distance between the folds of the envelope ( 12 ) in the axial direction along the rod ( 14 ) vary. The nucleus replacement according to claim 1, wherein on one side of the sheath ( 12 ) are arranged more folds than on the other side of the envelope ( 12 ). The nucleus replacement according to claim 1, further comprising an anchor ( 32 . 36 ) for attachment to the disc structure. The nucleus replacement according to claim 1, further comprising a guide wire ( 40 ) for the introduction of the envelope ( 12 ). The nucleus replacement according to claim 1, wherein the sheath ( 12 ) is formed of at least a polyurethane, a latex material, a natural rubber, a silicone rubber, a nylon or a shape memory polymer.